Guide To The 7 Most Popular Types Of Eryngium

If you have ever been drawn to a plant with an intriguing, spiky texture and a mesmerising metallic sheen, you have likely encountered an Eryngium. Commonly known as Sea Holly, this diverse and striking genus of plants is celebrated for its unique architectural beauty. 

They are a favourite among gardeners and florists for their resilience and dramatic flair. This guide will walk you through the most popular types of Eryngium, helping you discover the perfect variety to bring a touch of the extraordinary to your garden, balcony, or floral arrangements.

The Classic Blue Eryngium Varieties

When most people think of Sea Holly, they picture a brilliant, metallic blue. This is the most iconic colour in the genus, and these blue varieties are prized for their intense and long-lasting colour in the garden and the vase.

1. Eryngium planum (Flat Sea Holly)

Eryngium planum is perhaps the most widely grown and versatile of all the Sea Hollies. Native to Southeastern Europe and Central Asia, it is known for its reliability and hardiness. It produces an abundance of small, egg-shaped, steel-blue flower heads on highly branched stems, creating a wonderful haze of blue in a garden border. The plant forms a basal rosette of heart-shaped leaves, from which the tall flower stalks emerge.

One of the best things about Eryngium planum is the number of excellent cultivars it has produced. For those with limited space, such as an HDB balcony, 'Blue Hobbit' is a fantastic choice. It is a compact, dwarf variety that reaches only about 20-30 centimetres in height but still produces a profusion of classic blue flowers. 

At the other end of the spectrum is 'Blue Glitter', a popular cultivar known for its slender, shimmering stems and a huge number of small, intensely blue flowers that seem to sparkle in the sun.

2. Eryngium x zabelii

This group of Eryngiums consists of hybrids between Eryngium alpinum and Eryngium bourgatii. These hybrids are highly sought after because they combine the best traits of their parents, resulting in plants with large, intensely coloured flowers and beautiful foliage. They are known for their robust nature and exceptionally vibrant colour.

The most famous cultivar from this group is 'Big Blue'. As its name suggests, everything about this plant is dramatic. It produces very large, cone-shaped flower heads surrounded by long, spiky bracts. The most remarkable feature is the vivid, electric-blue colour that suffuses not just the flowers and bracts but also the upper stems, creating a truly spectacular display. 

'Big Blue' is a fantastic feature plant in a garden and is one of the absolute best varieties for use as a cut flower due to its size and intense colour.

3. Eryngium alpinum (Alpine Sea Holly)

For a slightly softer and more refined look, Eryngium alpinum is an exceptional choice. Native to the alpine regions of Europe, this species stands out because its surrounding bracts are not as stiff and prickly as other varieties. Instead, they are finely divided and feathery, forming a soft, intricate collar around the large, dome-shaped flower head. 

The colour is typically a deep and enchanting violet-blue. This delicate, lacy appearance makes it a particularly elegant addition to garden designs and floral arrangements. A popular cultivar is 'Blue Star', which is noted for its large flowers and brilliant colour.

Striking Silver and White Eryngium Types

While blue is the classic colour, some of the most dramatic and talked-about Eryngiums are found in shades of silver and white. These varieties offer a ghostly, ethereal beauty that contrasts wonderfully with other plants.

4. Eryngium giganteum ('Miss Willmott's Ghost')

No discussion of Eryngium is complete without mentioning the legendary Eryngium giganteum, more famously known as 'Miss Willmott's Ghost'. This plant has a wonderful story behind its name. It is named after Ellen Willmott, a wealthy and passionate gardener from the late 19th and early 20th centuries. She was known to carry seeds of this plant in her pocket and secretly scatter them in the gardens she visited, ensuring the plant would mysteriously appear long after she had left.

'Miss Willmott's Ghost' is a biennial, meaning it completes its life cycle over two years. In the first year, it forms a rosette of green leaves. In the second, it sends up a tall, branching flower stalk that produces huge, cone-like flowers surrounded by very large, spiky, and luminous silvery-white bracts. 

The effect is incredibly dramatic and ghostly. While the parent plant dies after flowering, it readily self-seeds, ensuring a continuous presence in the garden.

5. Eryngium maritimum (Sea Holly)

This is the true, original Sea Holly, found growing wild on coastal sand dunes across Europe. Eryngium maritimum is perfectly adapted to its harsh, windswept environment. It is a lower-growing plant with a sprawling habit and thick, waxy, silver-grey leaves that are resistant to salt spray. 

The flower heads are rounded and a pale, powdery blue, surrounded by stout, holly-like bracts. While it might not be as vibrant as other cultivars, its tough nature and authentic coastal character make it a unique choice for gardeners looking to create a specific seaside or gravel garden aesthetic.

Other Notable Eryngium Species for the Adventurous Gardener

Beyond the common blues and whites, the Eryngium genus has other fascinating species that offer different colours and forms for those looking to try something a little different.

6. Eryngium amethystinum (Amethyst Sea Holly)

As its name suggests, Eryngium amethystinum is prized for its beautiful amethyst-violet to blue colouring. Native to the Balkans and Italy, this species has a more slender and delicate branching habit compared to the robust Eryngium planum. 

The flower heads are smaller and more numerous, creating a fine, airy texture in the garden. Its unique colouring makes it a sophisticated choice that pairs beautifully with silver-foliaged plants and pastel-coloured flowers.

7. Eryngium yuccifolium (Rattlesnake Master)

Rattlesnake Master is an Eryngium that completely breaks the mould. At first glance, you might not even recognise it as a Sea Holly. Native to the tallgrass prairies of North America, it has long, sword-like, blue-green leaves that look very much like those of a Yucca plant. 

The flowers are also different; they are creamy white, spherical globes without the large, spiky bracts of their European cousins. It has a strong, upright form and provides a completely different texture in the garden. It is a fantastic choice for a naturalistic or prairie-style planting scheme.

Understanding the Eryngium Genus

Before diving into the specific varieties, it is helpful to understand what makes an Eryngium an Eryngium. These plants are instantly recognisable by their distinctive flower structure. What appears to be a single flower is actually a cone-shaped cluster of many tiny, tightly packed flowers. 

This central cone is surrounded by a dramatic collar of spiky, often colourful, leaf-like structures called bracts. It is this combination of cone and bracts that gives the plant its signature thistle-like appearance and architectural form.

What Makes a Plant an Eryngium?

All plants in the Eryngium genus share these core characteristics, along with a general preference for sunny, dry conditions. They are typically hardy perennial flowers, meaning they live for several years, though some are biennial. 

A common question that arises is whether Eryngium is a true thistle. Despite its prickly look, it is not. Thistles belong to the Asteraceae family, whereas Eryngium is a surprising member of the Apiaceae family, making it a relative of carrots, parsley, and celery. 

This relation is more apparent if you look closely at the tiny individual flowers that make up the central cone.

Choosing the Right Eryngium for Your Needs

With so many options, you can choose an Eryngium for almost any purpose. Whether you have a small balcony, want flowers for cutting, or wish to support local wildlife, there is a Sea Holly for you.

Best Eryngium Types for Small Spaces and Containers

For urban gardeners in Singapore, container planting is key. The best choice for pots is a dwarf variety like Eryngium planum 'Blue Hobbit'. Its compact size ensures it will not outgrow its container, while still providing that classic Sea Holly look. When growing any Eryngium in a pot, the most crucial factor is drainage. Use a gritty, sandy potting mix and ensure the pot has plenty of drainage holes.

Top Varieties for Cut and Dried Flower Arrangements

Many Eryngiums are fantastic for floral work. For a bold, statement stem, Eryngium 'Big Blue' is unmatched due to its large size and intense colour. For more versatile filler, the numerous stems of Eryngium planum and its cultivars are ideal. 

All these varieties are excellent for drying. They hold their shape and colour exceptionally well, making them a staple for everlasting bouquets and arrangements.

Creating a Pollinator-Friendly Garden with Eryngium

One of the greatest benefits of growing Eryngium is its value to wildlife. The flower heads are rich in nectar and pollen, which makes them flowers that attract pollinators, including bees, butterflies, and hoverflies. Planting a patch of Sea Holly is a simple and beautiful way to support the local ecosystem. 

A mix of varieties like Eryngium planum and Eryngium giganteum can provide a long season of blooms for these beneficial insects.

How to Grow Eryngium Successfully

Eryngiums are generally low-maintenance plants, but they do have a few essential requirements to thrive. Getting these right is the key to success.

Ideal Growing Conditions: Sun and Soil

The two non-negotiable needs for Eryngium are full sun and well-drained soil. They require at least six to eight hours of direct sunlight each day to produce strong stems and intense colour. In the shade, they will become floppy and weak.

Excellent drainage is even more critical, especially in a tropical climate with heavy rainfall. Eryngiums have a long taproot that will quickly rot if left in soggy, waterlogged soil. For garden beds, amend the soil with plenty of sand or horticultural grit to improve drainage. For pots, use a cactus or succulent potting mix, or create your own by mixing regular potting soil with equal parts sand or perlite.

Watering and Maintenance

Once established, Eryngiums are incredibly drought-tolerant thanks to their deep taproot. They prefer to be kept on the dry side. Water them deeply but infrequently, allowing the soil to dry out completely between waterings. They require very little fertiliser; in fact, overly rich soil can lead to weak growth. They are truly plants that thrive on a bit of neglect.

Eryngium Companion Plants

Eryngium looks best when planted alongside other sun-loving, drought-tolerant plants. This creates a cohesive and low-maintenance garden design. Great companions include Lavender, Russian Sage (Perovskia), Coneflower (Echinacea), Sedum, and various ornamental grasses. The spiky texture of Eryngium provides a stunning contrast to the soft forms of these other plants.

Conclusion On The Types of Eryngium

The Eryngium genus offers an incredible array of choices for any gardener or flower lover. From the classic electric blues of 'Big Blue' to the ghostly, silvery elegance of 'Miss Willmott's Ghost', there is a Sea Holly to suit every taste. 

These plants provide not only unique architectural beauty and texture but also resilience and low-maintenance charm. By choosing the right variety for your space, you can enjoy their striking presence and support local pollinators, adding a touch of wild drama to your home and garden.

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Frequently Asked Questions About Types of Eryngium

How Many Types of Eryngium Are There?

The genus Eryngium is very diverse, containing over 250 different species. These species are found across the globe in a wide range of habitats, from coastal sand dunes to alpine meadows. This diversity has also led to the development of many more cultivated varieties (cultivars) for garden use.

What Is the Most Popular Eryngium?

Eryngium planum (Flat Sea Holly) and its cultivars, like 'Blue Hobbit' and 'Blue Glitter', are among the most popular and widely grown types. Additionally, dramatic varieties like Eryngium x zabelii 'Big Blue' and the historically famous Eryngium giganteum 'Miss Willmott's Ghost' are exceptionally popular with gardeners and florists.

Is Eryngium a Thistle?

No, despite its spiky, thistle-like appearance, Eryngium is not a true thistle. Thistles are members of the Asteraceae family (the daisy family). Eryngium belongs to the Apiaceae family, which makes it a relative of plants like carrots, parsley, and celery.

Where Does Eryngium Grow Best?

Eryngium grows best in a location that receives full sun, meaning at least six to eight hours of direct sunlight per day. It is essential that it is planted in very well-drained soil, as it cannot tolerate wet conditions, which can cause its roots to rot. It thrives in poor, sandy, or gravelly soils.

Is Eryngium Hard to Grow?

No, Eryngium is generally considered easy to grow, provided its basic needs are met. As long as you give it plenty of sun and well-drained soil, it is a very low-maintenance and resilient plant. It is drought-tolerant once established and does not require frequent watering or fertilising.

Does Eryngium Come Back Every Year?

Most Eryngium species are perennials, which means they will live for several years and come back every year. However, a few prominent types, like Eryngium giganteum ('Miss Willmott's Ghost'), are biennial. This means they grow leaves in their first year, flower and produce seed in their second year, and then die. These biennial types often self-seed, so new plants will appear nearby.